Truck (bogie)

Truck: two-axle chassis connected
on a pivot to the main chassis, allowing the car to go around curves.Inflated carrying tire: tire inflated with compressed air.Current bar: part that slides along the electric circuit.Inflated guiding tire: tire inflated with compressed air that
guides the car along the track.Guiding bar: track along which the guiding tires roll.Runway: track along which the guiding tires roll.Running rail: track along which the safety wheels roll.Steel safety wheel: security wheel.

Photo :

EN : Subway
train

FR : Rame
de métro

ES : Subterráneo

A subway or metro system is a railway,
usually in an urban area, with a high capacity and frequency of service,
and grade separation from other traffic. In most parts of the world
these systems are known as a "metro", in London the system
is called the "Underground", while in most of North America
and in Glasgow, Scotland it is a "subway".